Employer Identification Number
The Employer Identification Number (EIN), also known as the Federal Employer Identification Number (FEIN) or Federal Tax Identification Number, is a unique nine-digit number in the format XX-XXXXXXX assigned by the United States Internal Revenue Service (IRS) to identify business entities, tax-exempt and non-profit organizations, estates, trusts, and other entities for federal tax administration purposes.[1][2][3] An EIN functions as a tax identifier analogous to a Social Security Number for individuals, allowing the IRS to track tax obligations, filings, and compliance for the associated entity.[4][5] It is essential for reporting federal income taxes, employment taxes, excise taxes, and taxes on alcohol, tobacco, and firearms, as well as for withholding taxes on non-wage income paid to nonresident aliens.[1] Beyond tax matters, businesses commonly use an EIN to open corporate bank accounts, apply for business credit or loans, hire employees, and obtain necessary licenses or permits.[6] Numerous types of entities require an EIN, including sole proprietorships with employees, partnerships, corporations, limited liability companies (LLCs), estates, trusts, and farmer's cooperatives.[1] Tax-exempt organizations, such as charities and non-profits under section 501(c), must obtain an EIN regardless of whether they have employees, as it uniquely identifies them to the IRS for filing requirements like Form 990.[7] Even entities without immediate tax liabilities, such as certain trusts or international organizations operating in the U.S., may need one for banking or regulatory compliance.[4] Obtaining an EIN is free and straightforward, with the IRS providing an online application tool that issues the number immediately upon approval for eligible U.S.-based applicants.[8] Alternatively, applicants can submit Form SS-4 by fax (processed within four business days) or mail (processed in about four weeks), or by telephone (immediate issuance) for entities formed outside the U.S. or U.S. territories.[2][9] The process requires basic information about the entity, such as its legal structure, responsible party, and reason for applying, ensuring the number remains valid indefinitely unless the entity's structure changes significantly.[1]Overview
Definition and Purpose
The Employer Identification Number (EIN), also known as a Federal Employer Identification Number (FEIN) or Federal Tax Identification Number, is a unique nine-digit number assigned by the Internal Revenue Service (IRS) in the format XX-XXXXXXX to identify business entities, estates, trusts, and other organizations for federal tax purposes.[10] This identifier serves as a permanent account number for the entity within the U.S. tax system, distinct from temporary or state-specific numbers.[1] The primary purposes of an EIN include enabling the filing of various business tax returns, reporting income and expenses to the IRS, paying employment taxes such as Social Security and Medicare withholdings, and facilitating the identification of entities in IRS records for compliance and auditing.[10] It is essential for entities engaging in activities that trigger federal tax obligations, including those involving employees or specific excise taxes, and supports non-tax functions like opening business bank accounts or applying for business licenses.[1] By providing a standardized identifier, the EIN streamlines tax administration and ensures accurate tracking of financial transactions separate from personal finances.[10] Unlike personal identifiers such as the Social Security Number (SSN), which is issued to individuals for personal tax and benefit purposes, an EIN is designated exclusively for entities and business-related activities to maintain separation between personal and organizational tax responsibilities.[10] Individuals operating a sole proprietorship may obtain an EIN to distinguish business transactions from their personal SSN, particularly when hiring employees or forming certain structures, but it cannot substitute for an SSN in personal contexts.[1] An EIN is issued free of charge by the IRS and can be obtained immediately upon submission of a valid application through the official online portal, available during business hours from Monday to Friday.[10] This process ensures quick access for eligible entities without any associated fees or delays for electronic submissions.[1]History
The Employer Identification Number (EIN) originated in 1936 as part of the implementation of the Social Security Act, when the IRS established a numbering system to identify employers for tracking contributions and administering the emerging social insurance program.[11] Prior to this, there was no standardized federal identifier for business entities in tax administration, and employers relied on ad hoc methods for reporting purposes.[11] By the mid-20th century, as the IRS expanded its role in business taxation, many entities—particularly sole proprietorships and small partnerships—routinely used the owner's Social Security Number (SSN) as their tax identifier, a practice that blurred the lines between personal and business records.[12] This approach led to significant privacy risks, as SSNs were disclosed in business contexts beyond their original intent of tracking individual earnings, and it created administrative challenges in distinguishing personal from entity-level tax obligations.[12] In 1974, amid growing concerns over data privacy that culminated in the Privacy Act of 1974 restricting mandatory disclosure of SSNs by federal agencies, the IRS formalized the EIN as the dedicated identifier for business tax purposes through Treasury Decision 7306, which amended regulations under the Internal Revenue Code to define its use and established the standardized nine-digit format for entities filing business returns. This shift effectively replaced SSN reliance for most business tax identification to safeguard personal information. Following 1974, the EIN's scope broadened beyond initial employment tax uses to encompass non-profit organizations, estates, trusts, and other non-business entities requiring federal tax accounts, reflecting the IRS's need for a unified identification framework across diverse filers.[10] During the 1990s, as electronic tax filing gained traction with the introduction of IRS e-file in 1986 and its expansion to business returns in 1988, EINs were integrated into digital systems to enable automated validation and processing of returns. This integration accelerated in the 2000s with advancements in IRS infrastructure, culminating in the launch of the online EIN application in 2003, which allowed instant issuance and reduced processing times from weeks to minutes for eligible applicants.[13]Acquisition
Who Requires an EIN
An Employer Identification Number (EIN) is mandatory for various business entities and organizations in the United States to facilitate tax reporting and compliance with Internal Revenue Service (IRS) requirements. Corporations, partnerships, and limited liability companies (LLCs) generally require an EIN upon formation or operation, as these structures necessitate separate identification for tax purposes distinct from individual owners.[8] Sole proprietors without employees or excise tax obligations are an exception and may use their Social Security Number (SSN) for tax filing, though obtaining an EIN is recommended to protect personal information and enable certain business activities.[10] Additionally, estates and trusts must obtain an EIN to file income tax returns, such as Form 1041, which reports income, deductions, and distributions.[14] Specific scenarios trigger the need for an EIN beyond entity type. Hiring employees requires an EIN for withholding income taxes, paying employment taxes, and reporting payroll, including for household employees filing Schedule H.[8] Entities engaged in paying sales, excise, alcohol, tobacco, or firearms taxes, or those required to withhold taxes on non-wage income, must also secure an EIN.[1] Furthermore, an EIN is essential for opening business bank accounts, applying for business licenses, and complying with IRS withholding rules for foreign nationals.[1] Tax-exempt organizations, including non-profits and churches, require an EIN for IRS recognition and tax-exempt status applications, even without employees, to identify the entity in dealings with federal, state, and local agencies.[7] Foreign entities operating in the U.S., such as those engaged in a trade or business, must obtain an EIN if required to file federal tax returns or comply with withholding regulations; exceptions apply to those not conducting U.S. activities.[15] This ensures proper tracking of tax obligations for international operations.[16]Application Process
The primary method for obtaining an Employer Identification Number (EIN) is through the online application system provided by the Internal Revenue Service (IRS) on its official website, irs.gov. This service is available Monday through Friday from 7:00 a.m. to 10:00 p.m. Eastern Time and allows eligible U.S.-based applicants to receive their EIN immediately upon successful submission, typically within minutes.[8][17] Applicants must provide specific information during the online process, including the legal name and mailing address of the entity, the name and Social Security Number (SSN) or Individual Taxpayer Identification Number (ITIN) of the responsible party (the individual who controls, manages, or directs the entity), the date the business started or will start, the reason for applying (such as starting a new business or hiring employees), and the type of entity (e.g., sole proprietorship, partnership, LLC, or corporation).[8][18] International applicants with a principal place of business outside the United States are not eligible for the online application and must use alternative methods.[17][1] For those unable to apply online, the IRS accepts applications via Form SS-4, Application for Employer Identification Number, which can be submitted by fax or mail. The form requires the same core information as the online application, including details on the entity's legal name, trade name (if applicable), address, responsible party's identification, start date, reason for applying, and entity classification, with additional lines for specifics like the number of employees or principal activity.[2][18] Domestic fax submissions (within the U.S. or D.C.) are sent to 855-641-6935, while international fax submissions are sent to 855-215-1627 if faxing from within the U.S. or 304-707-9471 if outside the U.S., with processing typically completed within four business days if a fax number is provided for return.[1][9] Mail applications for domestic applicants are directed to Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999, and for international or U.S. territory applicants to Internal Revenue Service, Attn: EIN International Operation, Cincinnati, OH 45999, generally taking about 4 to 5 weeks to process.[9][19] International applicants may also apply by telephone at 267-941-1099, available Monday through Friday from 6:00 a.m. to 11:00 p.m. Eastern Time, where an IRS representative will complete the application over the phone and issue the EIN immediately if approved.[1][9] A key limitation across methods is that only one EIN can be issued per responsible party per day via the online system, helping prevent misuse.[8] Third-party designees, such as attorneys or accountants, may assist with the application if authorized by the applicant. For online and paper applications, this authorization is indicated on Form SS-4 Line 18 (for paper) or through a signed power of attorney for online submissions, allowing the designee to receive the EIN and respond to IRS questions about the form.[9][8][18]Structure and Format
Number Composition
The Employer Identification Number (EIN) is a nine-digit identifier formatted as XX-XXXXXXX, where the first two digits represent a prefix assigned by the Internal Revenue Service (IRS), followed by a hyphen and seven additional digits.[10] Unlike the Social Security Number, an EIN does not include an embedded check digit for mathematical validation.[4] EINs are issued sequentially through IRS systems, either by designated IRS campuses handling paper or fax applications or via the online application portal, with no geographic coding embedded in the number beyond the prefix.[15] The IRS assigns these numbers upon approval of Form SS-4, ensuring each is unique and tied permanently to the entity.[2] Validation of an EIN occurs primarily through IRS internal systems, which check against the Business Master File using algorithms to confirm format, prefix validity, and entity association during tax filings or applications.[15] For public verification, entities may use IRS tools such as the TIN Matching Program for payers or third-party services integrated with IRS data for business compliance and filings, though direct public lookup of full EIN details is restricted to protect privacy.[20] EINs are never reused or reassigned to another entity once issued, remaining permanently associated even if deactivated due to inactivity.[21] Invalid formats, such as those starting with prefixes 00, 07, 08, 09, 17, 18, 19, 28, 29, 49, 69, 70, 78, 79, 89, 96, or 97, are rejected by IRS systems during assignment or processing.[15]Prefix Meanings
The first two digits of an Employer Identification Number (EIN), referred to as the prefix, identify the IRS campus or service center responsible for assigning the number, or indicate if it was issued through the online application process.[4] This prefix system facilitates internal IRS operations, such as routing taxpayer correspondence to the appropriate processing center and tracking the origin of issuance for administrative purposes.[15] It was established following the 2001 centralization of EIN assignments across IRS campuses to distribute workload more efficiently, shifting from a prior system where prefixes denoted the geographic location of the business.[10] Specific prefix ranges are allocated to each IRS campus as of November 2025. For instance, prefixes 10 and 12 are used by the Andover campus, 60 and 67 by the Atlanta campus, 40 and 44 by the Kansas City campus, 80 and 90 by the Ogden campus, and 30, 32, 35, 36, 37, 38, and 61 by the Cincinnati campus. Other campuses include Austin (50, 53), Brookhaven (01–06, 11, 13, 14, 16, 21–23, 25, 34, 51, 52, 54–59, 65), Fresno (15, 24), Memphis (94, 95), and Philadelphia (multiple, including 33, 39, 41–43, 48, 62–64, 66, 68, 71–77, 82–88, 91–93, 98, 99).[4][15] Online applications through the IRS's Modernized Internet EIN system typically receive prefixes from the internet allocation, such as 20, 26, 27, 33, 39, 45–47, 81, 82–88, 92, 93, or 99, while certain international or military-related applications (e.g., for addresses using APO or FPO designations) are assigned prefix 66 by the Philadelphia campus.[15] Prefix 66 is specifically reserved for such domestic foreign address cases, including some government entities with unique filing needs.[15] The IRS periodically adjusts prefix assignments to reflect organizational changes and workload shifts among campuses, ensuring balanced processing capacity. Recent updates as of May 2025 include expansions to internet prefixes. For the most current full list, refer to IRS resources.[22][4] In contrast, the middle five digits and the final two digits of an EIN have no specific meaning beyond serving as a sequential identifier to complete the unique nine-digit number.[10]| IRS Campus | Example Prefixes |
|---|---|
| Andover | 10, 12 |
| Atlanta | 60, 67 |
| Cincinnati | 30, 32, 35, 61 |
| Kansas City | 40, 44 |
| Ogden | 80, 90 |